I've just realised that my kitchen "appliance" radial circuit (4mm TWE) does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at least 50mm inside the ceiling, then surface wired all the way to the sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine and waste disposal unit (we dont have a dish washer). The washing machine socket will be under the sink but at the top front to keep it away from the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is an exterior socket available.

I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?

Simon.

"sm_jamieson" wrote in message
...
I've just realised that my kitchen "appliance" radial circuit (4mm TWE)
does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at
least 50mm inside the ceiling, then surface wired all the way to the
sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine
and waste disposal unit (we dont have a dish washer). The washing machine
socket will be under the sink but at the top front to keep it away from
the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is
an exterior socket available.

I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?

If you have already done it why change?

On May 21, 11:12*am, "dennis@home"
wrote:
"sm_jamieson" wrote in message

...

I've just realised that my kitchen "appliance" radial circuit (4mm TWE)
does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at
least 50mm inside the ceiling, then surface wired all the way to the
sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine
and waste disposal unit (we dont have a dish washer). The washing machine
socket will be under the sink but at the top front to keep it away from
the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is
an exterior socket available.

I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?

If you have already done it why change?

RCDed sockets do provide a small safety plus, especially in a wet room
like a kitchen. I also wouldnt be surprised if the 18th or 19th
requires all sockets to be on an RCD. Since you're all set up for one,
and its only £10 more than an mcb, I'd probably fit one.


NT

On 21/05/2012 10:43, sm_jamieson wrote:
I've just realised that my kitchen "appliance" radial circuit (4mm TWE) does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at least 50mm inside the ceiling, then surface wired all the way to the sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine and waste disposal unit (we dont have a dish washer). The washing machine socket will be under the sink but at the top front to keep it away from the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is an exterior socket available.

I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?

Since you already have it, is there any point changing it? If you later
need the space in the CU, then you can alter things...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
sm_jamieson writes:
I've just realised that my kitchen "appliance" radial circuit (4mm TWE) does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at least 50mm inside the ceiling, then surface wired all the way to the sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine and waste disposal unit (we dont have a dish washer). The washing machine socket will be under the sink but at the top front to keep it away from the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is an exterior socket available.
I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?
Simon.

If it's only used for fixed/stationary appliances, then that's OK.

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I haven't done a kitchen since 17th Edition came out, but I normally
did kitchens with 2 socket outlet circuits:

Not RCD protected (with sockets positioned to be not easily accessible):
For items which you don't want sharing an RCD (fridge, freezer,
frost protection (central heating), life support (fish tank, but using
own dedicated RCD);
Fixed/stationary items which can generate leakage without being
faulty (electric oven).

RCD protected:
All accessible socket outlets, e.g. worktop, walls.
All portable appliances.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Monday, May 21, 2012 12:29:00 PM UTC+1, John Rumm wrote:
On 21/05/2012 10:43, sm_jamieson wrote:
I've just realised that my kitchen "appliance" radial circuit (4mm TWE) does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at least 50mm inside the ceiling, then surface wired all the way to the sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine and waste disposal unit (we dont have a dish washer). The washing machine socket will be under the sink but at the top front to keep it away from the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is an exterior socket available.

I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?

Since you already have it, is there any point changing it? If you later
need the space in the CU, then you can alter things...


I've not wired it up either end of the circuit yet. The cable is in but not connected to the CU or the socket.
Simon.

On Monday, May 21, 2012 12:46:35 PM UTC+1, Andrew Gabriel wrote:
In article ,
sm_jamieson writes:
I've just realised that my kitchen "appliance" radial circuit (4mm TWE) does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at least 50mm inside the ceiling, then surface wired all the way to the sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine and waste disposal unit (we dont have a dish washer). The washing machine socket will be under the sink but at the top front to keep it away from the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is an exterior socket available.
I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?
Simon.

If it's only used for fixed/stationary appliances, then that's OK.

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I haven't done a kitchen since 17th Edition came out, but I normally
did kitchens with 2 socket outlet circuits:

Not RCD protected (with sockets positioned to be not easily accessible):
For items which you don't want sharing an RCD (fridge, freezer,
frost protection (central heating), life support (fish tank, but using
own dedicated RCD);
Fixed/stationary items which can generate leakage without being
faulty (electric oven).

RCD protected:
All accessible socket outlets, e.g. worktop, walls.
All portable appliances.


Yep, it was just a question of whether to RCD the fixed appliance radial and put the fridge freezer on its own non-RCD circuit, or make the radial non-RCD and include the fridge freezer on it.
The sockets in the base units need to be faily accessible since they are the method of isolation as well !
I think its been established previously that a fitted kitchen is part of the "building fabric" (although *most* of the cabinet sockets will be fixed to the rear wall with a cutout in the cabinet), and that an accessible unswitched plug is a suitable method of isolation.
Cheers,
Simon.

Andrew Gabriel wrote:
In article ,
sm_jamieson writes:
I've just realised that my kitchen "appliance" radial circuit (4mm
TWE) does not need an RCD !
It is surface mounted through the undertairs cupboards, visible
until at least 50mm inside the ceiling, then surface wired all the
way to the sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing
machine and waste disposal unit (we dont have a dish washer). The
washing machine socket will be under the sink but at the top front
to keep it away from the water. The other sockes will be at the top
back of the cabinets. None of these sockets are likely to be used
for outside power - there is an exterior socket available.
I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?
Simon.

If it's only used for fixed/stationary appliances, then that's OK.

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I belive that the only thing than Simon needs to do to comply with the 17th
is to label the socket so that they become "dedicated sockets". As always
some common sense is needed. A dedicated but easily accessible fridge socket
by the back door would not be allowed.

--
Adam

On May 21, 1:38*pm, sm_jamieson wrote:
On Monday, May 21, 2012 12:46:35 PM UTC+1, Andrew Gabriel wrote:
In article ,
* *sm_jamieson writes:
I've just realised that my kitchen "appliance" radial circuit (4mm TWE) does not need an RCD !
It is surface mounted through the undertairs cupboards, visible until at least 50mm inside the ceiling, then surface wired all the way to the sockets behind or in the cabinets.
The circuit will have sockets for gas hob, cooker hood, washing machine and waste disposal unit (we dont have a dish washer). The washing machine socket will be under the sink but at the top front to keep it away from the water. The other sockes will be at the top back of the cabinets.
None of these sockets are likely to be used for outside power - there is an exterior socket available.
I have wired a dedicated non-RCD circuit for the fridge.
Question is, do I forget this and save a space in the CU ?
Simon.

If it's only used for fixed/stationary appliances, then that's OK.

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I haven't done a kitchen since 17th Edition came out, but I normally
did kitchens with 2 socket outlet circuits:

Not RCD protected (with sockets positioned to be not easily accessible):
For items which you don't want sharing an RCD (fridge, freezer,
frost protection (central heating), life support (fish tank, but using
own dedicated RCD);
Fixed/stationary items which can generate leakage without being
faulty (electric oven).

RCD protected:
All accessible socket outlets, e.g. worktop, walls.
All portable appliances.

Yep, it was just a question of whether to RCD the fixed appliance radial and put the fridge freezer on its own non-RCD circuit, or make the radial non-RCD and include the fridge freezer on it.
The sockets in the base units need to be faily accessible since they are the method of isolation as well !
I think its been established previously that a fitted kitchen is part of the "building fabric" (although *most* of the cabinet sockets will be fixed to the rear wall with a cutout in the cabinet), and that an accessible unswitched plug is a suitable method of isolation.
Cheers,
Simon.

If you run cable you may as well run one more with it. Cable's cheap,
work and disruption less so. Then you can do what you like both now
and later. Its going to be there for 40 years or so, during which time
regs will change.


NT

On 2012-05-21, ARWadsworth wrote:

I belive that the only thing than Simon needs to do to comply with the 17th
is to label the socket so that they become "dedicated sockets". As always
some common sense is needed. A dedicated but easily accessible fridge socket
by the back door would not be allowed.

You mean write "FRIDGE" on the socket with a Sharpie?

On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster & similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?


(In any case, I would want RCD protection on all the sockets over the
worktop anyway, especially near the sink.)

Adam Funk wrote:
On 2012-05-21, ARWadsworth wrote:

I belive that the only thing than Simon needs to do to comply with
the 17th is to label the socket so that they become "dedicated
sockets". As always some common sense is needed. A dedicated but
easily accessible fridge socket by the back door would not be
allowed.

You mean write "FRIDGE" on the socket with a Sharpie?

Biro.

--
Adam

Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable
appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster & similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

It is. But Simon's setup meets the requirements for no RCD protection

http://wiki.diyfaq.org.uk/index.php?...and_Protection

http://wiki.diyfaq.org.uk/index.php?...lectric_cables


(In any case, I would want RCD protection on all the sockets over the
worktop anyway, especially near the sink.)

The wiki needs updating. Neither of those pages mention the RCD rule for
sockets.

--
Adam

In article ,
Adam Funk writes:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster & similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

The main claimed reason for the change was to prevent electrocution
of those who drill into cables. However, the incidence of this was
pretty insignificant (it was two cases in something like 8 years).
It was driven by the manufacturers to sell more RCDs, and sadly
that's how much of the wiring regs are driven nowadays.

However, the main purpose of [30mA] RCDs is as I said, protection
of electrocution from portable appliances. Other benefits pale
into insignificance in comparison with that one.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.
(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On May 22, 12:18*am, John Rumm wrote:
On 21/05/2012 20:47, Adam Funk wrote:

On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& *similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. *No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.
(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

--
Cheers,

John.

/================================================== ===============\
| * * * * *Internode Ltd - *http://www.internode.co.uk* * * * * *|
|-----------------------------------------------------------------|
| * * * *John Rumm - john(at)internode(dot)co(dot)uk * * * * * * *|
\================================================= ================/

Interesting - the only time I've had an RCD trip was when the fan
motor in the cooker oven went leaky. I appreciate that the
regulations may well not regard this as a necessary bit of kit for RCD
protection (from what I'm reading above), but if it had blown on the
MCB, there would have been a significantly big bang, blue flash and
acrid smoke, none at all pleasant from previous experience, whereas
with the RCD it just tripped politely and wouldn't reset so obviously
a fault to be located.

Regardless of the regulations, I would rather have everything on an
RCD/RCBO and avoid the heavy current required to trip an MCB.

Rob

On May 21, 9:42*pm, (Andrew Gabriel)
wrote:
In article ,
* * * * Adam Funk writes:

On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster & similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. *No?

The main claimed reason for the change was to prevent electrocution
of those who drill into cables. However, the incidence of this was
pretty insignificant (it was two cases in something like 8 years).
It was driven by the manufacturers to sell more RCDs, and sadly
that's how much of the wiring regs are driven nowadays.

However, the main purpose of [30mA] RCDs is as I said, protection
of electrocution from portable appliances. Other benefits pale
into insignificance in comparison with that one.

There's also fires due to L-E current, which RCDs trip on.


NT

On 2012-05-21, Andrew Gabriel wrote:

In article ,
Adam Funk writes:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster & similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

The main claimed reason for the change was to prevent electrocution
of those who drill into cables.

That's what I thought, because of the "mechanically protected" exception.

However, the incidence of this was
pretty insignificant (it was two cases in something like 8 years).
It was driven by the manufacturers to sell more RCDs, and sadly
that's how much of the wiring regs are driven nowadays.

Aha.


However, the main purpose of [30mA] RCDs is as I said, protection
of electrocution from portable appliances. Other benefits pale
into insignificance in comparison with that one.

I can understand the need for RCD protection outdoors or near water
(e.g., near the sink), but is it really a problem inside the rest of
the house?

I get the impression a lot of people are annoyed about the
proliferation of RCDs because they think (rightly or wrongly) that
their sockets are now more susceptible to nuisance trips, which are
especially a nuisance for computer equipment, PVRs, &c..

On 2012-05-21, John Rumm wrote:

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.

Right, because they are more likely to get wet, if nothing else.


(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

In article ,
Adam Funk wrote:
On 2012-05-21, John Rumm wrote:

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.

Right, because they are more likely to get wet, if nothing else.


(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

"portable" is anything that is plugged in, rather than being permanently
connector (to a fused spur).

--
From KT24

Using a RISC OS computer running v5.18

Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

In article ,
Adam Funk writes:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.
I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster & similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?
The main claimed reason for the change was to prevent electrocution
of those who drill into cables.

That's what I thought, because of the "mechanically protected" exception.

However, the incidence of this was
pretty insignificant (it was two cases in something like 8 years).
It was driven by the manufacturers to sell more RCDs, and sadly
that's how much of the wiring regs are driven nowadays.

Aha.


However, the main purpose of [30mA] RCDs is as I said, protection
of electrocution from portable appliances. Other benefits pale
into insignificance in comparison with that one.

I can understand the need for RCD protection outdoors or near water
(e.g., near the sink), but is it really a problem inside the rest of
the house?

I get the impression a lot of people are annoyed about the
proliferation of RCDs because they think (rightly or wrongly) that
their sockets are now more susceptible to nuisance trips, which are
especially a nuisance for computer equipment, PVRs, &c..

Well it depends what kit you have. Old fashioned steel cased
heaters..dodgy insulation and earth..yes you want an RCD.


other kit? no.

BUT its a handy tool to ID if you have damp wiring or a dodgy appliance.

--
To people who know nothing, anything is possible.
To people who know too much, it is a sad fact
that they know how little is really possible -
and how hard it is to achieve it.

On 22/05/2012 09:06, robgraham wrote:
On May 22, 12:18 am, John wrote:
On 21/05/2012 20:47, Adam Funk wrote:

requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.
(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

Interesting - the only time I've had an RCD trip was when the fan
motor in the cooker oven went leaky. I appreciate that the
regulations may well not regard this as a necessary bit of kit for RCD
protection (from what I'm reading above), but if it had blown on the
MCB, there would have been a significantly big bang, blue flash and
acrid smoke, none at all pleasant from previous experience, whereas
with the RCD it just tripped politely and wouldn't reset so obviously
a fault to be located.

Yup that is the flip side benefit. The usual downside of RCDs on cookers
is when the heating element itself gets a little leaky (either in
moisture or electrical terms - the two often being related). The RCD can
prevent its operation, whereas being able to run it will drive off
enough moisture to stop it being so leaky, and keep it serviceable for
some time longer.

Regardless of the regulations, I would rather have everything on an
RCD/RCBO and avoid the heavy current required to trip an MCB.

Depending on the nature of the fault you may not get the choice... ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 22/05/2012 13:20, Adam Funk wrote:
On 2012-05-21, John Rumm wrote:

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.

Right, because they are more likely to get wet, if nothing else.

More to the point, the user is more likely to be standing on wet ground
and hence be well earthed. So the risks from direct connection to
something live are significantly greater.

(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

Anything that is not fixed really.

With something like a hob or a cooker hood, there is fairly limited
scope for faults that could put the user at risk of a shock. Whereas
with things that have flexible cords that allow it to be moved about,
there are plenty more ways to either damage the flex or get the powered
appliance into places where it would be better off not being.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 22/05/2012 13:35, charles wrote:
In ,
Adam wrote:
On 2012-05-21, John Rumm wrote:

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.

Right, because they are more likely to get wet, if nothing else.


(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

"portable" is anything that is plugged in, rather than being permanently
connector (to a fused spur).

Near enough, although I would treat a built in single oven connected via
a 13A plug as a fixed appliance. Same as a boiler connected in the same
way.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

NT wrote:
On May 21, 9:42 pm, (Andrew Gabriel)
wrote:
In article ,
Adam Funk writes:

On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle,
toaster, etc), then I would strongly suggest you do RCD protect
it.
RCD protection is mostly for the added safety of portable
appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in
the plaster & similar kinds), since the main new thing has to do
with cables near the surface without mechanical protection. No?

The main claimed reason for the change was to prevent electrocution
of those who drill into cables. However, the incidence of this was
pretty insignificant (it was two cases in something like 8 years).
It was driven by the manufacturers to sell more RCDs, and sadly
that's how much of the wiring regs are driven nowadays.

However, the main purpose of [30mA] RCDs is as I said, protection
of electrocution from portable appliances. Other benefits pale
into insignificance in comparison with that one.

There's also fires due to L-E current, which RCDs trip on.

which working RCDs trip on.

--
Adam

In article ,
Adam Funk writes:
On 2012-05-21, John Rumm wrote:

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.

Right, because they are more likely to get wet, if nothing else.


(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

Something you could move. In this context, the RCD protection is
most applicable for appliances which could get dropped, left in
the rain, cable yanked, stepped on, etc, e.g. damaged by virtue
of being portable. A washing machine would normally be a stationary
or fixed appliance. It's less likely to end up faulty in a way which
leaves it live (it may well get an internal short to the chassis,
but it is very likely to have a working earth connection). Experience
has shown that faults which leave an appliance live are most likely
to happen with portable appliances, and least likely with stationary
and fixed appliances.

Toaster seems to be a frequent cause of trips here, largely because
people seem to jab it with cutlery to clear out the piece of whatever
they just burned to a cinder in it, without unplugging it.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 2012-05-22, John Rumm wrote:

On 22/05/2012 13:20, Adam Funk wrote:
On 2012-05-21, John Rumm wrote:

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.

Right, because they are more likely to get wet, if nothing else.

More to the point, the user is more likely to be standing on wet ground
and hence be well earthed. So the risks from direct connection to
something live are significantly greater.

Yes, I think when I wrote "they" I meant the appliances and the users.


(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

Anything that is not fixed really.

With something like a hob or a cooker hood, there is fairly limited
scope for faults that could put the user at risk of a shock. Whereas
with things that have flexible cords that allow it to be moved about,
there are plenty more ways to either damage the flex or get the powered
appliance into places where it would be better off not being.

Fair point, but is anywhere else in the world pushing RCDs everywhere
the way the current British regulations are? (Not that that makes the
British ones right or wrong, but I'm curious.)

On 2012-05-22, Andrew Gabriel wrote:

In article ,
Adam Funk writes:
On 2012-05-21, John Rumm wrote:

(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

Something you could move. In this context, the RCD protection is
most applicable for appliances which could get dropped, left in
the rain, cable yanked, stepped on, etc, e.g. damaged by virtue
of being portable. A washing machine would normally be a stationary
or fixed appliance. It's less likely to end up faulty in a way which
leaves it live (it may well get an internal short to the chassis,
but it is very likely to have a working earth connection). Experience
has shown that faults which leave an appliance live are most likely
to happen with portable appliances, and least likely with stationary
and fixed appliances.

Toaster seems to be a frequent cause of trips here, largely because
people seem to jab it with cutlery to clear out the piece of whatever
they just burned to a cinder in it, without unplugging it.

Yes, "toaster" was a bad choice of example!

"Adam Funk" wrote in message
...
On 2012-05-22, John Rumm wrote:

On 22/05/2012 13:20, Adam Funk wrote:
On 2012-05-21, John Rumm wrote:

On 21/05/2012 20:47, Adam Funk wrote:
On 2012-05-21, Andrew Gabriel wrote:

If it's also used for portable worktop appliances (kettle, toaster,
etc), then I would strongly suggest you do RCD protect it.
RCD protection is mostly for the added safety of portable appliances.

I'd assumed (yes, I know) that the main point of the new RCD
requirements was to deal with the risk of cable damage (nail in the
plaster& similar kinds), since the main new thing has to do with
cables near the surface without mechanical protection. No?

Yes. However don't also forget the old RCD requirements for protecting
sockets that may potentially be used to power appliances used outside.

Right, because they are more likely to get wet, if nothing else.

More to the point, the user is more likely to be standing on wet ground
and hence be well earthed. So the risks from direct connection to
something live are significantly greater.

Yes, I think when I wrote "they" I meant the appliances and the users.


(or the general preference for RCD protection on any circuit that
supplied portable appliances used anywhere)

What's "portable" in this case? Something light enough that you
*could* move it around frequently (e.g., toaster but not washing
machine), or something that you would *normally* move around (e.g.,
laptop, power drill)?

Anything that is not fixed really.

With something like a hob or a cooker hood, there is fairly limited
scope for faults that could put the user at risk of a shock. Whereas
with things that have flexible cords that allow it to be moved about,
there are plenty more ways to either damage the flex or get the powered
appliance into places where it would be better off not being.

Fair point, but is anywhere else in the world pushing RCDs everywhere
the way the current British regulations are? (Not that that makes the
British ones right or wrong, but I'm curious.)

Yes, Australia does too now.
http://en.wikipedia.org/wiki/Residua...vice#Australia

Some others in that wiki too.

On 22/05/2012 13:35, charles wrote:

"portable" is anything that is plugged in, rather than being permanently
connector (to a fused spur).

Not in BS 7671-world. The definitions are pretty clear:

- 'fixed equipment' is anything /designed/ to be "fastened to a support
or otherwise secured in a specific location," regardless of the means of
connection;

- 'portable equipment' is now a deprecated term, superseded by 'mobile
equipment' being "equipment which can be moved while in operation or
which can easily be moved [...] /while connected to the supply/".

[Ref. BS 7671:2008 Part 2]

--
Andy

Toaster seems to be a frequent cause of trips here, largely because
people seem to jab it with cutlery to clear out the piece of whatever
they just burned to a cinder in it, without unplugging it.

Those people who jam my toaster with waffles
and other such french / american abominations
deserve to be shocked.

[g]